In the manufacture of semiconductors or semiconductor microcircuits it is necessary to remove materials from the surface of the substrate of the semiconductor device. In some instances the materials to be removed are polymeric compositions referred to as photoresists. In other instances the materials to be removed are residues of etching or ashing processes or simply contaminants. The purpose of stripping and/or cleaning compositions is to remove unwanted materials from a semiconductor substrate without corroding, dissolving or dulling the exposed surface of the substrate.
The art contains numerous references to compositions of different types for use in stripping photoresist and/or cleaning etch residue, ash or other contaminants from semiconductor substrates. For example a series of patents issued to Allied Signal disclose nonaqueous organic stripping compositions comprising one or more organic sulfonic acids in conjunction with organic solvents and various improvements. The first patent in the series U.S. Pat. No. 4,165,295 discloses a composition for removing polymeric organic substances such as photoresist comprising one or more organic, sulfonic acids one or more organic solvents, optionally a phenol and from about 5 to 250 ppm of a fluoride ion. The second patent U.S. Pat. No. 4,215,005 provides an improvement in the composition where in the fluoride is present in conjunction with a complexing agent having a nitrogen with an available unshared electron pair. The third patent in the series U.S. Pat. No. 4,221,674 provides another improvement in the composition where between 0.01 to 5 weight % of a nitrile compound is added to the composition. The fourth patent in the series U.S. Pat. No. 4,242,218 comprises a phenol free stripping composition comprising a sulfonic acid in admixture with chlorinated aryl compounds, alkylaryl compounds having 1–14 alkyl carbon atoms an isoparaffinic hydrocarbon or mixtures thereof.
U.S. Pat. No. 5,308,745 discloses alkaline containing photoresist stripping compositions having reduced metal corrosion containing non-nitrogen containing weak acids having a pK in an aqueous solution of 2.0 or higher and an equivalent weight of less than about 140. The weak acids are employed in an amount that will neutralize from 19% to 75% of the amine present in the composition. U.S. Pat. No. 5,972,862 discloses a cleaning liquid for semiconductor devices comprising a fluoride containing compound, a water soluble organic solvent, inorganic or organic acids and optionally a quaternary ammonium salt or carboxylic acid ammonium salt and/or organic carboxylic acid amine salt. U.S. Pat. No. 6,231,677 discloses the use of one or more carboxylic acids in stripping compositions. WO 00/02238 discloses a cleaning chemistry based on a choline compound such as choline hydroxide. The compositions are comprised of a choline compound, water and an organic solvent. The compositions may in addition contain hydroxyl amine and a corrosion inhibitor.